4ou9 | pdb_00004ou9

Crystal structure of apocarotenoid oxygenase in the presence of Triton X-100

spinqualitylabelsall models 4ou9, resolution 2.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4ou9 is a 4 chain structure with sequence from Synechocystis sp. PCC 6803 substr. Kazusa. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: CL, FE2 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function ACOX_SYNY3 Cleaves a number of carotenals and carotenols in the all-trans configuration at the 15-15' double bond producing retinal or retinol, respectively. Also shows activity toward lycopenals and the corresponding alcohols. Does not cleave beta-carotene or lycopene. Publication Abstract from PubMed Carotenoid cleavage enzymes (CCEs) constitute a group of evolutionarily related proteins that metabolize a variety of carotenoid and non-carotenoid substrates. Typically, these enzymes utilize a non-heme iron center to oxidatively cleave a carbon-carbon double bond of a carotenoid substrate. Some members also isomerize specific double bonds in their substrates to yield cis-apocarotenoid products. The apocarotenoid oxygenase from Synechocystis has been hypothesized to represent one such member of this latter category of CCEs. Here, we developed a novel expression and purification protocol that enabled production of soluble, native ACO in quantities sufficient for high resolution structural and spectroscopic investigation of its catalytic mechanism. High-performance liquid chromatography and Raman spectroscopy revealed that ACO exclusively formed all-trans products. We also found that linear polyoxyethylene detergents previously used for ACO crystallization strongly inhibited the apocarotenoid oxygenase activity of the enzyme. We crystallized the native enzyme in the absence of apocarotenoid substrate and found electron density in the active site that was similar in appearance to the density previously attributed to a di-cis-apocarotenoid intermediate. Our results clearly demonstrated that ACO is in fact a non-isomerizing member of the CCE family. These results indicate that careful selection of detergent is critical for the success of structural studies aimed at elucidating structures of CCE-carotenoid/retinoid complexes. Analysis of carotenoid isomerase activity in a prototypical carotenoid cleavage enzyme, apocarotenoid oxygenase (ACO).,Sui X, Kiser PD, Che T, Carey PR, Golczak M, Shi W, Von Lintig J, Palczewski K J Biol Chem. 2014 Mar 19. PMID:24648526 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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